Hydraulic motor



Mar ch24, 1959 E. c. STOLTZ ETAL HYDRAULIC MOTOR Filed March 25, 1957.

3 Sheets-Sheet l 4 FIG.

INVENTORS ELMER C. STOLTZ WILLIAM J. ZEEVELD ELMER J. STOLTZ ATT..

E. c. STOLTZ ET AL 2,878,787

March 24, 1959 HYDRAULIC MOTOR 3 Sheets-Sheet 3 Filed March 25, 1957 INVENTORS ELMER C.STOLTZ WILLIAM J.

ELD Z Ev ELMESJ. STOLT BY ATTY.

United States Patent HYDRAULIC MOTOR Elmer C. Stoltz, Sacramento, William J. Zeeveld, North Sacramento, and Elmer J. Stoltz, Castro Valley, Calif.

Application March 25, 1957, Serial No. 648,153

6 Claims. (Cl. 121-119) The present invention relates to improvements in a hydraulic motor intended to convert hydraulic flow and pressure into useful torque.

More particularly, it is proposed to provide a machine of the character described in which steel balls are used to convert hydraulic pressure into rotary motion, the steel balls being guided rectilinearly while subject to thedriving energy of liquid under pressure, and being made to engage in spiral grooves provided in the rotor for revolving the latter.

It is further proposed to provide means for reciprocating the steel balls with respect to the rotor so that each stroke is a power stroke, whereby the etficiency of the motor is greatly increased.

And finally, it is proposed to arrange the motor in such a manner as to combine two similar drives into one unit, the drives being spaced angularly to substantially eliminate dead center effects.

Further objects and advantages of our invention will appear as the specification proceeds, and the .new and useful features of our invention will be fully defined in the claims attached hereto.

The preferred form of our invention is illustrated in the accompanying drawings,.forming part of this application, in which:

Figure 1 shows a plan view of our motor;

Figure 2, a vertical, horizontal section through the same;

Figure 3, a transverse section taken along line 33 of Figure 2; and

Figure 4, a vertical section taken along line 4-4 of Figure 2.

While we have shown only the preferred form of our invention, it should be understood that various changes or modifications may be made within the scope of the claims attached hereto, without departing from the spirit of the invention.

Referring to the drawings in detail, our invention comprises in its main features, a pair of cylinders 5 and 6 arranged in alined relation and substantially identical in form, except for angular displacement, a central connecting piece 7 having two caps 8 and 9 suitably secured upon the confronting ends of the cylinders, two caps 10 and 11 secured upon the outer ends of the cylinders, and two rotors 12 and 13 revolvable within the cylinders and of the same length as the cylinders.

Each cylinder is formed with two longitudinal grooves 14 in the inner face thereof, the grooves being straight and extending from end to end and being arranged in diametrically opposed relation. It will be noted that the cylinder 5 is turned to an angle of 90 degrees with respect to the cylinder 6, so that its grooves 14 are on the far and near side of the cylinder.

The grooves are semi-circular in cross-section, and are made to have an easy, sliding fit with the outer halves of the steel balls 15 to be more particularly referred to hereinafter.

2,878,787 Patented Mar. 24, 1959 Each rotor comprises a heavy cylindrical body commensurate in length with thecylinders and hollowed to present axial feed conduits 16, and each rotor has reduced axial extensions 17 taking bearing in the caps.

The two outer extensions are splined together, as at 18, and all the extensions are made to form a continuous feed line with the rotors, into which a pressure medium, such as oil, is forced from the right end (see Figure 2), through a connecting pipe 19.

At the left end, the feed line is continued sufliciently far to answer its purposes, as at 20, and then changes into a solid shaft 21 serving as a power take-off.

Each of the two rotors 12 and 13 is formed with a pair of spiral grooves 22 disposed on oposite sides thereof and running to form reverse threads. Each of the grooves extends clear from end to end, and is made to occupy somewhat less than half of the circumference of the rotor, the ends of the two grooves of each rotor end being spaced approximately by the width of the longitudinal grooves 14, as shown in Figure 3.

The spiral grooves are semi-circular in cross-section and are complementary to the longitudinal grooves, so that, at any point of intersectiomthe longitudinal and spiral grooves define a circular passage having a close fit with the interposed ball 15. This fit should be as near liquid-tight as possible.

At opposite ends of each longitudinal groove, each of the caps 8-11 is formed witha cylindrical pocket 23 drawn to the same radius as the longitudinal and spiral grooves and having an outer half lined up with the longitudinal groove and an inner half adapted for lining up with the end of a passing spiral groove, so that, when the end of the spiral groove passes the end of the longitudinal groove, the ball 15 may be ejected into the pocket, over the resistance of a spring 24 disposed in the far end of the groove.

The spring 24 is placed under tension by the ejected ball and is intended to initiate return movement of the ball in the opposite direction when the end of the second spiral groove lines up with the end of the longitudinal groove.

Each of the pockets is formed with a port 25 extending radially toward its co-related axial extension 17 of the rotor, and each of the extensions is formed with a peripheral port 26 for each of the ports 25, each port 26 being adapted for lining up with the port 25 during approximately one-half of a revolution, so as to admit the pressure medium into the pocket during said period.

The port 25 joins the pocket 23 behind the ball so that the pressure medium urges the ball toward and through the grooves to impart rotary motion to the rotor.

As the ball is forced through the grooves, it finds itself faced by a body of liquid left from the previous operation in the opposite direction, and this liquid is ejected through a radial passage 27 in the end face of the rotor made to communicate with an outlet port 28 in the corresponding cap during the ejection period.

It should be understood, of course, that the pressure system could be a closed system including a pump, with the ports 28 connected to the pump intake and the conduit 19 connected to the pump outlet, so that the pump suction would aid in evacuating the grooves ahead of the advancing ball.

In operation:

Starting with the position shown in Figure 2, with the balls of the left unit exerting rotary torque on the left rotor and the balls 15 of the right unit confined in their respective pockets and with the ends of the spiral grooves about to enter into a position of registry with the ends of the longitudinal grooves:

When the ends of the spiral grooves register with the ends of the longitudinal grooves, the balls 15 are snapped intothe circular opening formed by the two grooves, by the springs 24.

At the same time, the ports 26 of the feed conduit 16 are made to register with'the ports 25 leading to the pockets, and the pressure medium enters behind the balls and urges the same forward in the longitudinal grooves 14 in opposite directions, the balls bearing on the walls of the spiral grooves and causing the rotor to rotate.

Again, at the same time, the passage 27 at the opposite end of the rotor is made to register with its respective port 28 to allow any liquid ahead of the ball to be ejected by the ball, aided by suction created in the pressure system.

As the two balls reachthe ends of the grooves, they are pushed into the pocket, and each is ready for re-entry as soon as the next spiral'groove reaches the pocket.

The second unit operates on the same principle, and is mounted for driving at a90 degree angle to avoid dead points in the operation of the motor.

We claim:

1. In a. hydraulic motor of the character described a cylindrical housing having a longitudinal groove in the inside wall thereof, a rotor revolvable in the housing rotor so as to allow the 'ball to escape when reaching coresponding ends of the grooves, and the housing having' an end cap forming a pocket adapted to receive the escaping ball with spring means in said pocket placed under tension by the escaping ball and operative to exert pressure on the ball in the direction of the longitudinal groove. 2. In a hydraulic motor of the character described, a cylindrical housing having a longitudinal groove in the inside wall thereof and extending from end to end, a. rotor revolvable in the housing and having a pair of registering spiral grooves on opposite sides thereof, with the spiral grooves extending from end to end and spaced at their ends, and a ball reversibly movable in the longitudinal groove and successively engageable in the spiral grooves for applying rotary torque to the rotor in the same direction when the ball is advanced in either direction.

3. In a hydraulic motor of the character described, a cylindrical housing having a longitudinal groove in the inside wall thereof and extending from end to end, a

rotor revolvable in the housing and having a pair of registering spiral grooves on opposite sides thereof, with the spiral grooves extending from end to end and spaced at their ends, and a ball reversibly movable in the longitudinal groove and successively engageable in the spiral registering spiral grooves on opposite sides thereof, with the spiral grooves extending from end to end and spaced at their ends, and a ball reversibly movable in the longi tudinal groove and successively engageable in the spiral grooves for applying rotary torque to the rotor in the same direction when the ball is advanced in either direction, the housing having caps at opposite ends with pockets in the caps adapted to accommodate the ball while shifting from one spiral groove to the other, and the pockets having spring means operable to be placed under compression by the ball as the latter is ejected from one spiral groove and to initiate return movement into the other spiral groove.

5. In a hydraulic motor of the character described, a cylindrical housing having a longitudinal groove in the inside wall thereof, and extending from end to end, a rotor revolvable in the housing and having a pair of registering spiral grooves on opposite sides thereof, with the spiral grooves extending from end to end and spaced at their ends, and a ball reversibly movable in the longitudinal groove and successively engageable in the spiral grooves for applying rotary torque to the rotor inthe same direction when the ball is advanced in either direction, the housing having caps at opposite ends with pockets in the caps adapted to accommodate the ball while shifting from one spiral groove to the other, and the pockets having spring means operable to be placed under compression by the ball as the latter is ejected from the spiral groove and to initiate return movement into the other spiral groove, and the caps and the rotor hav ing cooperative means for admitting a pressure medium to the pocket rearwardly of the ball.

6. In a hydraulic motor of the character described, a cylindrical housing having a longitudinal groove in the inside wall thereof, and extending from end to end, a rotor revolvable inthe housing and having a pair of registering spiral grooves on opposite sides thereof, with the spiral grooves extending from end to end, and spaced at their ends, and a ball reversibly movable in the longitudinal groove and successively engageable in the spiral grooves for applying rotary torque to the rotor in the same direction when the ball is advanced in either direction, the housing having caps at opposite ends with pockets in the caps adapted to accommodate the ball while shifting from one spiral groove to the other, and the pockets having spring means operable to be placed under compression by the ball as the latter is ejected from the spiral groove and to initiate return movement into the other spiral groove, and the caps and the rotor having cooperative means for admitting a pressure medium to the pocket containing the ball for driving the latter and for relieving the pressure ahead of the ball.

References Cited inthe file of this patent UNITED STATES PATENTS 572,593 Barney Dec. 8, 1906 1,142,641 Temple June 8, 1915 2,246,733 Kiefer June 24, 1941 FOREIGN PATENTS 82,066 Austria Dec. 27, 1920 

